An image display device, which converts an image generated and supplied from a display device, such as a liquid crystal (LC) display device or an electro luminescence (EL) display device, into a virtual image using a virtual image optical system and supplies the same to an observer, is commonly known.
Such an image display device is being applied to recently widely used wearable display devices such as, for example, head-mounted displays (HMDs), smart glasses, etc.
Further, the image display device is also being applied to head-up display devices, which display a virtual image indicating various information necessary for traveling to a point on a sight line of a pilot or a driver so that the virtual image is overlaid on the field of view ahead of the pilot or the driver.
A conventional image display device employs a polarization beam splitter in order to transfer light emitted from a light source to a display unit.
In general, a polarization beam splitter divides incident light into polarized components such that a P-wave component passes therethrough and an S-wave component is reflected therefrom and travels to a display unit. At this time, the display unit generates image light using the polarized light supplied from the polarization beam splitter.
However, there is a problem in that the polarization beam splitter is an expensive optical component and in that there is a limitation in the extent to which the size of the image display device can be reduced due to the space occupied by the polarization beam splitter.